The use of reverse osmosis (RO) purifiers has become a contentious issue, mainly because of the amount of water that is wasted following its use. Last May, the National Green Tribunal (NGT) issued an order to ban RO purifiers in cases where the total dissolved solids in the water source were less than 500 mg/litre. The order had come following a petition filed by a Delhi based NGO ‘Friends’ which had pleaded that indiscriminate use of RO filters was leading to huge wastage of water.

In response to the National Green Tribunal (NGT) order asking the centre to prohibit the use of reverse osmosis purifiers where total dissolved solids in water are below 500 milligrams per litre, the environment ministry has now issued a draft notification seeking user’s views before banning use of RO purifiers in areas which get potable water.

What are RO purifiers

RO purifiers are based on the process of Reverse Osmosis (RO) that offers multi-stage filtration of water by combining active carbon and also particle filtration. Water is made to pass through a membrane (a polymer film) that has very small-sized pores and this weeds out minerals and contaminants in the water. The impurities collected are then flushed out through an outlet pipe.

Is it really necessary to use them under all circumstances?

While RO purifiers are effective in cleaning contaminants, minerals such as iron, calcium, potassium that are essential for the body in small amounts are also removed in the process. The use of RO purifiers in the case of water with TDS lower than 500mg/litre can thus lead to weakened bones and other health problems because of the demineralisation of water. The other important drawback of RO filters is that they lead to a huge wastage of water, almost three fourth of what is processed, which is extremely undesirable in the context of India where the pressure on the water resources is increasing day by day.

And here is the catch in its use. While RO purifiers are very useful in places that have very high levels of contaminants and salts in the water, Indian markets have been promoting them even in places where their use is unnecessary, like that in places where the water is safe to drink and has low levels of Total Dissolved Solids (TDS) according to BIS norms.

What are the main points from the notification

The draft notification prohibits installation or use of Membrane Based Water Purification Systems (MWPS) - primarily reverse osmosis (RO) based systems where the water is in compliance with acceptable limits for drinking water prescribed by Bureau of Indian Standard 10500:2012 - Drinking Water Specification. It also says that water filtered from the RO purification system at the domestic level should only be used for drinking. Reject generated from domestic RO purifiers installed at point of use can be collected and used for non-drinking purposes and other uses as specified in guidelines to be prescribed by Central Pollution Control Board (CPCB).

Once the rules are finalised, RO manufacturers will have to modify their designs to meet the new parameters that require the new systems to conform to the need to prevent discharge of water beyond the prescribed limit during the purification process. The draft also states that all commercial and industrial installations of RO filters shall operate within the provision of The Water (Prevention and Control of Pollution) Act, 1974 and State Pollution Control Board/ Pollution Control Committee will ensure compliance.

The draft recommends that it is upto the BIS to develop a system and procedure to monitor, assess, and certify the quality of RO filters in consultation with the CPCB within six months of the final notification. The draft also leaves the responsibility of publishing a guideline on handling, storage, management and utilisation of reject generated from MWPS including management and disposal of discarded elements to the CPCB within six months of the final notification.

The draft notification puts the responsibility of enforcement on the CPCB and State Pollution Control Boards (SPCB) who can take the water supply agencies on board to certify if they provide potable drinking water in a particular area according to BIS standards.

The draft also lays down the rules for manufacturers and importers keeping in mind the quality, water conservation and environmental regulations in the country and informs that violation of norms should be brought to the SPCBs and CPCB or the environment ministry with the CPCB being the nodal agency for implementation of the rules.

The draft also talks about the efficiency of RO systems and rules and regulations on the disposal of waste elements from the RO filters that it specifies shall be considered as “plastic waste” within the provision of sub-section (q) of section 3 of the Plastic Waste Management Rules, 2016 and shall be used for energy recovery or waste to oil etc.

The ministry is seeking public comments on the draft which may be sent within thirty days after which the final notification on use of RO filters and the parameters for  their design will be decided. The comments can be sent to Jigmet Takpa, Joint Secretary CP (W) Division, Ministry of Environment, Forest and Climate Change, Indira Paryavaran Bhawan, Jor Bagh Road, New Delhi – 110 003, or to the Ministry at the e-mail address  takpa.jigmet@gov.in  and sundeep.moef@gmail.com  
 

The draft notification can be accessed at this link